Anthem Blue Cross, Aetna and PacifiCare have all agreed to delay their proposed health premium increases for 60 days, leaving Blue Shield of California as the only insurer in California to go ahead with plans to raise rates, Insurance Commissioner Dave Jones said Thursday.

Jones had asked Blue Shield this month to delay imposing rate hikes on its individual policyholders. Some members are seeing their rates go up by as much as 59 percent with new and recent increases. Several days later, he made the same request of the three other insurers.

While the other insurers have complied, officials at Blue Shield, with headquarters in San Francisco, have refused to delay the increases and plan to put the new rates into effect March 1. They say higher hospital and prescription drug costs are driving the premiums up. They have agreed to refund policyholders only if an independent actuary finds errors in its rate filings.

The insurer said Thursday that the review is on track to be completed before March 1.

"Blue Shield policyholders will not have the benefit of this additional review period to ensure compliance with the law, but I will do what is within my power to determine whether Blue Shield's proposed rates are in compliance with the law and to enforce that law," Jones said.

Jones' authority, however, is limited to making sure that insurers spend a certain portion of their premium dollars on direct medical care. On Tuesday, Jones got the go-ahead to enforce a new federal law that requires insurers to spend at least 80 percent on medical care, up from the previous threshold of 70 percent.

Anthem, which drew national attention last year for trying to raise rates 39 percent, wants to increase premiums an average of 9.8 percent. Aetna has filed for a 2.8 percent hike, and PacifiCare has proposed raising premiums from 2.5 to 9.1 percent.